<template>
  <div class="tags" v-if="showTags">
    <ul>
      <li
        class="tags-li"
        v-for="(item,index) in tagsList"
        :class="{'active': isActive(item.path)}"
        :key="index"
      >
        <router-link :to="item.path" class="tags-li-title">{{item.title}}</router-link>
        <span class="tags-li-icon" @click="closeTags(index)">
          <i class="el-icon-close"></i>
        </span>
      </li>
    </ul>
    <div class="tags-close-box">
      <el-dropdown @command="handleTags" class="drop-tags">
        <el-button size="mini" type="text" class="tags-btn-sel">
          <div class="btn-inner">
            <span>标签选项</span>
            <i class="el-icon-arrow-down el-icon--right"></i>
          </div>
        </el-button>
        <el-dropdown-menu slot="dropdown">
          <el-dropdown-item command="other">关闭其他</el-dropdown-item>
          <el-dropdown-item command="all">关闭所有</el-dropdown-item>
        </el-dropdown-menu>
      </el-dropdown>
    </div>
  </div>
</template>

<script>
import bus from './bus'
export default {
  data() {
    return {
      tagsList: []
    }
  },
  methods: {
    isActive(path) {
      return path === this.$route.fullPath
    },
    // 关闭单个标签
    closeTags(index) {
      const delItem = this.tagsList.splice(index, 1)[0]
      const item = this.tagsList[index]
        ? this.tagsList[index]
        : this.tagsList[index - 1]
      if (item) {
        delItem.path === this.$route.fullPath && this.$router.push(item.path)
      } else {
        this.$router.push('/')
      }
    },
    // 关闭全部标签
    closeAll() {
      this.tagsList = []
      this.$router.push('/')
    },
    // 关闭其他标签
    closeOther() {
      const curItem = this.tagsList.filter(item => {
        return item.path === this.$route.fullPath
      })
      this.tagsList = curItem
    },
    // 设置标签
    setTags(route) {
      const isExist = this.tagsList.some(item => {
        return item.path === route.fullPath
      })
      if (!isExist) {
        if (this.tagsList.length >= 8) {
          this.tagsList.shift()
        }
        this.tagsList.push({
          title: route.meta.title,
          path: route.fullPath,
          name: route.matched[1].components.default.name
        })
      }
      bus.$emit('tags', this.tagsList)
    },
    handleTags(command) {
      command === 'other' ? this.closeOther() : this.closeAll()
    }
  },
  computed: {
    showTags() {
      return this.tagsList.length > 0
    }
  },
  watch: {
    $route(newValue, oldValue) {
      this.setTags(newValue)
    }
  },
  created() {
    this.setTags(this.$route)
    // 监听关闭当前页面的标签页
    bus.$on('close_current_tags', () => {
      for (let i = 0, len = this.tagsList.length; i < len; i++) {
        const item = this.tagsList[i]
        if (item.path === this.$route.fullPath) {
          if (i < len - 1) {
            this.$router.push(this.tagsList[i + 1].path)
          } else if (i > 0) {
            this.$router.push(this.tagsList[i - 1].path)
          } else {
            this.$router.push('/')
          }
          this.tagsList.splice(i, 1)
          break
        }
      }
    })
  }
}
</script>


<style lang="less" scped>
.tags {
  position: relative;
  height: 46px;
  overflow: hidden;
  padding-right: 120px;
  padding: 4px 10px;
}

.tags ul {
  width: 100%;
  height: 100%;
  display: flex;
}

.tags-li {
  float: left;
  height: 100%;
  border-radius: 4px;
  font-size: 14px;
  overflow: hidden;
  cursor: pointer;
  line-height: 36px;
  border: 1px solid #e9eaec;
  margin-right: 10px;
  background: #fff;
  padding: 0 15px;
  vertical-align: middle;
  color: #999;
  -webkit-transition: all 0.3s ease-in;
  -moz-transition: all 0.3s ease-in;
  transition: all 0.3s ease-in;
}

.tags-li:not(.active):hover {
  background: #f8f8f8;
}

.tags-li.active {
  color: #fff;
  border: 0 none;
  line-height: 38px;
}

.tags-li-title {
  float: left;
  max-width: 80px;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
  margin-right: 5px;
  color: #999;
}

.tags-li.active .tags-li-title {
  color: #fff;
}

.tags-close-box {
  position: absolute;
  right: 10px;
  top: 4px;
  z-index: 10;
  text-align: center;
  width: 120px;
  height: 38px;
  border-radius: 4px;
  box-shadow: 0px 5px 25px 0px rgba(0, 0, 0, 0.08);
  background-color: #fff;
}
.tags-close-box .drop-tags {
  width: 100%;
  height: 100%;
}
.tags-btn-sel {
  width: 120px;
  height: 38px;
}
.btn-inner {
  display: flex;
  flex-direction: row;
  justify-content: space-around;
  align-items: center;
  color: #696974;
}
</style>
